Apple Aperture 2 - Manual (Page 417)

Chapter 15 Making Image Adjustments 417
III
Working with the Enhance Controls
You use the Enhance adjustment controls to set the contrast, definition, saturation, and
vibrancy, as well as the black, gray, and white tint values.
Adjusting Contrast in the Image
If you want to adjust the difference between the dark and bright areas of the image,
you can modify the Contrast parameter. An image with very little midtone tonality is
considered to have a lot of contrast, whereas an image with considerable midtone
tonality is considered to have minimal contrast. Often, an image with too much
midtone tonality looks flat. Adding contrast to the image can add depth to it. However,
you add contrast to the image at the expense of detail in the midtones, so a little
contrast goes a long way.
Before Contrast adjustment After Contrast adjustment